Spray pyrolysis synthesis of bimetallic NiMo/Al2O3–TiO2 catalyst for hydrodeoxygenation of guaiacol: Effects of bimetallic composition and reduction temperature

Abstract

Catalytic hydrodeoxygenation (HDO) is a process for removing of oxygen from oxygen-containing compounds using a catalyst. In this study, spherical bimetallic NiMo/Al2O3–TiO2 catalysts with different Ni/Mo ratios were successfully synthesized by combining sol–gel method and continuous flow spray pyrolysis process. The prepared catalysts were characterized by N2 adsorption–desorption, TEM, SEM, XRD, XPS, H2-TPR and NH3-TPD analyses. The catalysts were then applied for HDO of guaiacol as a model compound using a fixed-bed reactor. The effects of bimetallic compositions and reduction temperatures on HDO conversion of guaiacol as well as their product distributions were systematically investigated. The obtained results showed that bimetallic NiMo/Al2O3–TiO2 exhibited higher HDO conversion than monometallic catalysts (Ni/Al2O3–TiO2 or Mo/Al2O3–TiO2). The highest HDO conversion of 98% with 100% hydrocarbon selectivity (85% cyclohexane, 13% methylcyclohexane and 2% toluene) was obtained over (10 wt% Ni and 20 wt% Mo)/Al2O3–TiO2 catalyst. In addition, the catalyst maintained a good catalytic stability for 24 h of reaction time, suggesting that spray pyrolysis derived NiMo/Al2O3–TiO2 catalyst can be a promising catalyst for HDO performance.